1. Field of the Invention
The present invention relates to a centrifugal compressor which is configured to compress a gas such as air with centrifugal force, and is used for a turbocharger, a gas turbine, an industrial pneumatic system and the like.
2. Description of the Related Art
Brief descriptions will be provided for a configuration of a general centrifugal compressor used for a turbocharger such as a vehicle turbocharger.
The general centrifugal compressor includes a housing. The housing has a shroud (wall surface) in its inside. In addition, an impeller is rotatably provided inside the shroud of the housing in such a manner as to be rotatable about the axis of the impeller. The impeller includes: a disc (hub disc) rotatable about the axis of the impeller; and multiple blades provided at intervals on the outer peripheral surface of the disc.
A suction opening is formed in the outer wall of the housing. The suction opening is situated on the inlet side of the impeller, and sucks air as an example of a gas. In addition, an air discharging passage is formed in the housing. The air discharging passage is provided on the outlet side of the impeller, and discharges the compressed air. Furthermore, a discharge opening is formed in an appropriate position on the outer wall of the housing. The discharge opening communicates with the air discharging passage. The compressed air passes through the air discharging passage and is discharged from the discharge opening.
The impeller rotates when the centrifugal compressor is operated. The rotation makes it possible to compress the air, which is sucked from the suction opening into the impeller, by using centrifugal force and to discharge the compressed air from the discharge opening to the outside of the housing via the air discharging passage.
Incidentally, Japanese Patent Application Laid-Open Publication Nos. 2009-09694, 2004-27931 and H09-310699 disclose conventional techniques related to the present invention.